This invention relates to seedling planting devices. More particularly, the present invention is directed to a heavy duty tree seedling planting device adapted to open a furrow, insert a seedling therein, and repack the furrow to complete the planting process. The invention is believed most relevantly classified within United States Class 111.
In the prior art a variety of mechanized systems have previously been employed to plant tree seedlings or similar plants. Devices of this nature are of particular importance to the timber industry, which must plant millions of seedlings each year to properly maintain an inventory of developing trees.
Prior art mechanized planting systems generally employ a rigid structure including downwardly projecting, ground-engaging coulter plates and associated plow structure for opening a furrow. Various forms of automated or mechanized seedling feeder systems have been suggested to facilitate displacement of the seedlings from a remote hopper into proper position within the furrow. For example, it is well known to employ some form of mechanical picks or other members moved via chains or other drive means between seedling receptive and seedling dispensing positions. It is also known in the art to repack furrows with inclined repacking wheels.
The following prior art United States Patents incorporate one or more of the aforementioned principles: U.S. Pat. Nos. 2,463,938; 1,972, 281; 2,887,075; 1,906,139; 2,335,132; and 2,725,022. Examples of prior art patents which are believed most relevant to the present invention are U.S. Pat. Nos. 3,261,310; 3,643,611; and, 4,026,225.
Our experience has indicated that known prior art devices are generally unsuitable for dependable and continuous use in areas characterized by steep slopes and irregular terrain. Moreover, maneuverability of known prior art planters is severely compromised in extremely rocky soil, or soil in which other obstacles such as tree roots or the like may be encountered. While lighter models or designs of treeplanters will facilitate maneuverability, known lightweight machines are notoriously unreliable. For example, lightweight frames may become twisted or bent. Typically rubber compaction wheels, which tend to wear out or become punctured in extremely rough terrain, are used with lighter planters.
Heavier planters may be of sufficient strength to avoid damage to the frame or the plow assembly when rocks or other obstacles are encountered. However, the coulter wheel and the seedling feeding systems typically remain vulnerable to injury. One of the main problems with prior art systems is that the compaction wheels are not mounted for remote manipulation. Moreover, some prior art towing systems make it difficult to quickly maneuver the coulter wheel around buried obstacles.
Typically some form of feeding system is employed to transfer seedlings from storage hoppers to the furrow. A variety of machanized seedling conveyance systems have been suggested by the prior art. Such systems suffer from two main disadvantages. First, reliability of such systems is often compromised by the extremely hostile conditions encountered in practice. As mentioned, the land upon which trees are raised is often inhospitable to mechanized devices. Moreover, the planting season dictates use in the coldest and often wettest time of the year.
Another feeder problem concerns operator safety. Several instances of employee injury have occurred in the past from treeplanter feeding systems employing mechanized seedling picks or the like, which often come into inadvertent contact with the operators hand. Contact can occur, for example, when the unit unexpectedly encounters a severe bump or obstacle as it is being towed. Such shocks may throw the cab occupant into contact with the feeder. Thus a feeder which is incapable of injuring the operator, but which will function reliably in severe conditions of use, is clearly necessary.